5V input boost 7.2V two series lithium iron phosphate battery 1A charging board - PCB design scheme

1 Circuit board PCB description：

1.1 Name ： 5V input boost 7.2Vtwo series lithium iron phosphate battery 1A charging board

1.2 Applications:Convenient charging devices, etc.

1.3 Battery pack: 3.2Vlithium battery pack, two series 3.2V lithium battery ， full 8.4V

1.4 Input voltage: 5V（ When charging, the light will be on, and when it is fully charged,the light will turn）

1.5 Max charging current： 1A

1.6 Introduction to Chip Functions ：

1， Lithium battery charging circuit：PW4040

PW4040 Lithium battery charge management chip， Up to 3.5A charging current， adjustable output charging voltage,support wide input voltage

2， Circuit diagram ：

PCB layout is divided into two parts: signal controlcircuit + power circuit

Note 1： The blue thick line is the power trace, the layout should be wide,； SW part (Q1, D1, L1 three devices connected) is not only the poweroutput, but also it is a noise source, the layout should be wide and the area shouldbe small.

Note 2： The red thick line is the power ground, the main points of the drawing board: to bewide, the shorter the distance between the connecting loops at each point, the more holes are punched in the ground.(input, C5, C6, C10, C9, C8,Q1 and battery ground)

3， PCB diagram and 3Ddisplay diagram

4 ， BOM Material List .

Comment	Designator	Footprint	Quantity
0603 1uF 25V	C4， C3	0603A	2
0805 22uF 25V	C5, C6	0805C	2
0603 330pF 25V	C7	0603A	1
0805 10uF 25V	C8	0805C	1
0603 0.1uF 25V	C9	0603A	1
100uF 25V SMD Aluminum Capacitors 6.3MM	C10	SMD	1
0603 10uF 25V	C11	0603A	1
SS34 SMB	D1	SMB	1
Integrated molded inductor 0650 15UH	L1	SMD	1
LED RED 0603	LED1	0603A	1
MMBT3904	Q1, Q2, Q3	SOT23-3	3
LED Green 0603	LED2	0603A	1
PW4406	Q4	SOP8	1
0603 1MR 1%	R1	0603SL	1
0603 200K 1%	R2	0603SL	1
0603 22K 1%	R3，R9	0603SL	2
0603 1K 5%	R4, R5	0603SL	2
1210 80mR 1%	R6	1210R	1
0603 5.1K 1%	R1, R2	0603SL	2
PW4040	U1	SOT23-6	1
USB TYPE C 16PIN	USB1	USB	1